Storage Foundation API Emscripten Filesytem

This repo contains an Emscripten filesystem implementation that uses Storage Foundation API as a backend. It must be run within a Web Worker, since it uses the synchronous version of the API.

NOTE: This filesystem is incomplete, it will be updated (and cleaned) as more parts of Storage Foundation API become accessible. Missing pieces include rename, setting attributes, sub-directories, etc.

An example C++ program (example.cpp) is included. It show basic file operations and how to read a file from JavaScript.

The mount_filesystems.js script shows how multiple filesystems can be made accessible to one module.

How-To

To compile the example run:

emcc --js-library ./library_sfafs.js \
  --post-js ./mount_filesystems.js --post-js ./read_file.js \
  -s DEFAULT_LIBRARY_FUNCS_TO_INCLUDE='["$SFAFS","$MEMFS"]' \
  -o example.js example.cpp

To see the result run the following with Chrome M91 or higher:

emrun --serve_after_exit --no_browser index.html

And then open the following link in a Chrome instance with the "Experimental Web Platform features" flag enabled: localhost:6931.

Experimental Asynchronous Filesystem

An experimental attempt at an asynchronous Emscripten file system is included in folder async/. Unfortunately, it requires to modify the emscripten runtime by exchanging the syscalls in src/library_syscalls.js and src/library_wasi.js with their asynchronous counterparts of async/library_syscall_async.js. This has to be done by manually replacing them in the files; we are working on a more convenient method.